Turbine-rotor.



J. P. METTBN.

TURBINE ROTGR.

APPLIOATION FILED SEPT. 2e, 1913.

Patented May 19, 1914.

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inn srnrns PATENT ormoni- JOHN F. IVIETTEN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 THE WILLIAM CRAMP & SONS SHIP & ENGINE BUILDING COIVIPANY, A CORPORATION 0F PENN- SYLVANIA.

'IURBINE-R-OTOR.

Specification of Letters Patent.

Patented May 19, 1914.

To all whom t may concer/n.: Y

Be it known that I, JOHN F. MENEN, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have 1nvented certain new and useful Improvements in Turbine-Rotors, of which the following is a full, clear, and exact specication.

This invention relates to the rotating members of elastic fluid turbines wherein the parts are subjected to variations of temperature which cause expansion and contraction.

Where the hubs of the bucket wheels of steam turbines are rigidly fixed against longitudinal movement on the shaft, difference in longitudinal expansion between the wheel hubs and the shaft is liable to cause whipping or bending of the shaft. This may throw the movable blades or buckets out of position and may even cause them to collide with the stationary blades. This may cause the blades to strip and the turbine to be seriously damaged.

The main object of the present invention is to provide a means whereby the distortion and danger due to this unequal expansion may be avoided and this is accomplished by permitting the wheel hubs to move along the shaft as they expand.

@ther and ancillary objects of the invention will appear hereinafter.

The invention can be best described in connection with the accompanying drawings, of whichh Figure 1 is a central longitudinal section partly broken away, of a turbine embodying the invention; and Fig. 2 is a detail on an enlarged scale. l

Referring to the drawings, within the casing 1 turns the rotor shaft 2. The interior of the turbine is divided into stages by means of the fixed partitions or diaphragms 3. Vithin these stages are mounted the bucket wheels as t which carry the circumferential rows of buckets or blading 5 between which extend the stationary intermediate blading 6. The hubs 10 of the bucket wheels are slid upon the shaft 2 extending beneath the stationary diaphragms, and are held against rotation with relation to the shaft'by means of the keys 11. The hubs of the bucket wheels substantially cover the shaft and are held against longitudinal movement to the left by means o f a shoulder l2 which may be turned up on the shaft. The movement of hubs at the other end is limited by means of a nut 13 which is screw-threaded upon the shaft. Steam is admitted to the various stages byvmeans of nozzles as 7 in the diaphragme. In the turbine shown, provision is made for dierent speeds by varying the number of stages. Thus, in this structure, the highest speed is obtained when steam is admitted to the chamber 8 and to the nozzles leading therefrom, the stages to the right being cut out, another speed being obtained by admitting steam to the chamberl 9 .and through the nozzles leading therefrom, this including two more stages and reducing the speed, while a still further reduced speed may be obtained by admitting steam initially to the extreme right-hand stage.

Uien steam is first admitted to any of the stages of the turbine, it comes in ydirect contact with the wheel hubs and onfaccount of the leakage of the steam between the diaphragms and hubs this is the case throughout substantially the whole length of the hub. TheY result is thatrthe hubs expand under the heat received from the steamand before this heat is transmitted to the shaft. This causes unequal expansion of the shaft and hubs so that where suitable provision is not made for'this expansion the shaft is liable to be whipped or bowed with danger of blading or other parts of the turbine coming into collision, with resulta-nt damage to the turbine. In this structure clearance is provided between the stationary abutment at the left and the nut at the right to permit the longitudinal movement of the wheel hubs under expansion, and this clearance is distributed along the shaft, so that the relative movement of any given bucket wheel under Yexpansion is insignificant so far as blade clearances are concerned. This is accomplished by dividing the hubs into groups (two to a group in the structure shown) and placing abutments between the groups. l

provided between each pair of adjacent abuty movement of those hubs which are locatedbetween the abutments and so the necessary clearances for the wheel hubs will be distributed along the shaft and become insig-` nificant at any given point.

ln the structure shown the intermediate abutments 15 are removable so that the wheels can be readily assembled upon the shaft. These intermediate abutments are formed by making circumferential grooves inthe shaft at the points where abutments are desired, and in each of these grooves ay spring steel ring is sprung, this ring eX- tending outside ofthe groove and forming the abutment. rlhe ring may be secured in position by counter-boring an adjacent wheel hub so that it may overlap the ring. This structure is clearly shown in Fig. 2 wherein it appears that the wheel. hub 10 is limited as to its longitudinal movement on the shaft 2 by the ring 15 fitting in a groove in the shaft and extending outwardly therefrom, thehub 10 being counterboredA and over-lapping the ring 15 which it holds in position, the expansion clearance being indicated at 18.

While the invention is illustrated in what is considered its best application, it may have other embodiments without departing from its spirit and is not therefore limited to the structure shown in the drawings.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent, 'is

1. .An elastic'fluid turbine having a rotor comprising a shaft, a bucket wheel thereon, and means for limiting the longitudinal movement of the hub of said bucket wheel along said shaft but allowing for longitudinal heat expansion of said hub.

2; An elastic fluid turbine having a rotor comprising a shaft, a plurality of bucket wheels having their hubs mounted on said shaft and movable with relation thereto, and means forV limiting the movement of said hubs upon said shaft but permitting their longitudinal movement with relation" thereto under expansion by heat.

3. An elastic fluid turbine having a rotor comprising a shaft, a plurality of bucket wheels having their hubs mounted thereon and movable with relation thereto, and abutments on said shaft between whichthe hubsV are located and which limit Vtheir longitudinal movement but permit such movement under heat expansion.

Ll.- An elastic fluid turbine-having a rotor comprising a shaft, a pluralityk of bucket wheels having their hubs mounted thereon and movable with relation thereto, and abutments on said shaft between which the hubs are located and which limit their longitudinal movement but permit such movement under heat expansion, one of said abutments being adjustable.

5. An elastic fluid turbine having a rotor comprising a shaft, a plurality of bucket wheels having their hubs mounted thereon @and movable with relation thereto, and abutments on said shaft between which the hubs are located .and which limit their longitudinal. movement but permit such movement under heat expansion, one of said aboutments being a nut in screw-threaded engagementI with said shaft.

6. An' elastic fiuid turbine having a casing, diaphragms dividingVV the interior of the'ca'sing into stages, nozzles for admitting elastic fluid to the stages and a rotor comprising a shaft, bucket wheels in the stages, Vsaid bucket wheels having their hubs mounted upon and movable with relation to said shaft, and means for limiting the longitudinal movement of the hubs upon said shaft but permitting their movement due to heat expansion.

7. An elastic fluid turbine having a rotor comprising a shaft, bucket wheels having their hubs mounted thereon and movable longitudinally with relation thereto, means for limiting the longitudinal movement of said wheels along said shaft but providing a clearance to permit of the movement of tliewvlieel hubs under heat expansion, and means for distributing the-clearance along the shaft.

8. An elastic fluid turbinehaving a rotor comprising a shaft, aA plurality of bucket wheels having their hubs longitudinally movable upon said shaft, and a plurality of abutments along saidl shaft, a portion of the wheel hubs being included between two adjacent abutments.

9. An elastic iiuid turbine havinga rotor comprising a shaft, a plurality of bucket wheels having their hubs Vlongitudinally movable thereon, abutments at the ends of the hubs for limiting longitudinal movement thereof but providing for their longitudinal movement under heat expansion, and means located between the said abutments for dividing the expansion clearance betweenV a Yplurality of groups of bucket wheels.

10. In an elastic fluid turbine rotor, -the combination with a shaft having aY circumferential groove of a ring` in said groove and a bucket wheel having its hub over-lapping said ring.

11. An elastic fluid turbine having a casing, diaphragmsV dividing the interior of the easing into stages, nozzles for admitting Y Yelastic fluid te thestages and a rotor comprising a shaft, bucket wheels in the stages, In testimony whereof I aix my signasaid bcket whels hying their hubs ture, in presence of two witnesses.

mounte u on an Inova e with re ation to said shaft,p and a plurality of abutments Y JOHN F' METTEN along said shaft, a portion of the Wheel Witnesses:

hubs being included between two adjacent JAMES H. KURTZJ abutments. JOSEPH HECKING.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

